Hoist crane refers to the lifting equipment with electric hoist as the lifting mechanism. The most common refers to electric single-girder cranes. The hoist-type single-beam crane has a light structure and simple operation. The safety technology of the hoist-type single-beam crane is explained below.
The characteristics of hoist crane: light and compact structure, easy and convenient operation, wide range of applications, and many applications. However, there are generally no full-time operators, and there are no dedicated cable and command personnel. Operators often work as cable operators. Therefore, the potential accident factors will be more serious than other types of cranes.
1. Safety protection device of gourd type single beam crane
1. Mechanical safety device (guarantee the service life of the crane)
(1) Hook protection device: a protection device to prevent accidental decoupling of the hoisted load.
(2) Rope guide: to prevent accidents caused by messy ropes.
(3) Brakes: (all are mechanical brakes) rely on spring pressure and the friction force of the conical brake ring to brake.
(4) Stop (female feeder): set at appropriate positions at both ends.
(5) Buffer: Reduce the impact force of the collision between the crane and the stop, and the impact and vibration of the crane and the load. Hardwood, rubber polyurethane buffers.
2. Safety protection device
(1) Lift limit position limiter (heavy mound type)
(2) Limit position limiter (travel switch)
(3) When the safety alarm device (used in conjunction with the load limiter) reaches 90% of the rated value, it will send out a reminder alarm signal.
(4) Overload limiter
(5) Phase sequence protection (wrong phase protection)
2. Requirements for the safe use of hoist cranes in different environments
1. Use in dusty environment
(1) Operation should be carried out in a closed cab to protect the personal health of the driver.
(2) The protection level of the motor and main electrical appliances on the crane should be increased accordingly, mainly due to the dustproof ability.
2. Use in humid environment
Under normal circumstances, when the working environment humidity is not more than 85%, the protection level is IP44.
In a humid environment, a preheating and drying device should be added for motors above 10KW.
A rain cover should be added to the motor and electrical appliances of the hoist crane operating in the open air.
3. Use in high temperature environment
(1) The driver’s cab should be a closed driver’s cab equipped with electric fans or air-conditioning.
(2) Temperature control devices such as thermal resistance should be embedded on the motor windings and casing.
4. Use in cold environment
(1) Adopt a closed cab with heating device.
(2) Remove ice and snow from tracks, ladders and walking platforms in time to prevent slipping and falling injuries.
(3) The main force-bearing rod-type components of the crane shall be made of ordinary carbon steel conforming to the gold steel type and not less than Q-235-C.
5. Ground control
The non-following operation mode is adopted, that is, the operator does not move with the lateral movement of the hoisted load. The flashlight door is not suspended under the electric hoist switch box, but is separately suspended on a slideway, so that the operator may stay away from the hoisted load. Operate in a proper position to avoid the risk of impact from hanging loads.
When operating on the surface, the operating speed of the crane must be under the condition of V≤45M/min to prevent the operator from racing with the crane too fast.
3. Special safety protection measures for hoist cranes
1. Use in flammable and explosive occasions
(1) All electrical originals must not have exposed parts
(2) The insulation resistance value of the explosion-proof hoist crane at room temperature is not less than 1.5MΩ
(3) Track ground connection resistance is not more than 4Ω
(4) All explosion-proof electrical equipment shall have an explosion-proof certificate issued by the country-designated explosion-proof inspection unit within the validity period.
(5) To prevent sparks caused by mechanical frictional collision and dangerous temperature causing danger, the speed is limited, and the ropes shall not be greater than 25M/min
(6) There must be no broken wires on the surface of the wire rope
(7) The joints of the running track should be smooth and flat, and there should be no impact when the wheels are running.
(8) Hanging warning signs, “no collision”, “touching the ground”, etc.
(9) Brakes should be installed inside an explosion-proof enclosure
During the use of hoist-type single-beam cranes, attention should be paid to its operating safety, operating procedures should be followed, and illegal operations should be avoided. Enterprises should do a good job in the safety management of equipment.